Despite no natural sporting ability of any sort, and carried on a wave of Olympic fever last year after the Brownlees double triumph in Hyde Park, I signed up for the Blenheim and London triathlons. The British Triathlon Federation now has more than 15,000 members and there are more than 500 registered triathlon clubs. At least one of them, London Fields Triathlon Club, reported a spike in membership applications in August last year. Chairman Chris Skinner believes the ever-growing popularity of the sport is also down to a new "fitness is cool culture" and a more positive attitude. "Tri clubs are much more fun," he says. "I've been part of athletics, football and cricket club and they are more set in their ways. Anything is possible with tri!"

But when I first started thinking about the sport last September, I had no idea how much it would take over my life. Along with many new triathletes (if I dare call myself that), my weekends are now mainly spent in Lycra and my days tend to start and finish much earlier than I ever imagined, rising to get in an early cycle and collapsing into bed from exhaustion. A 6am start for swim sessions is tough but the open water practice is invaluable, especially in the dreaded washing machine-like mass start. Once you've had a 6"4in triathlete swim over you in practice it will – hopefully – seem less daunting on the day!

Triathlon is not a cheap sport. The largest part of your money will go on the bike – you can spend a fortune on these and get carried away with group sets and gadgets, but a standard racing bike will do. The largest part of the event is spent on the bike, so it makes sense to put in the hours. Unfortunately for me, the British weather didn't get the memo I sent requesting spring, so many of those hours have involved slogging away on a turbo trainer in my living room watching Breaking Bad box sets.

And that leaves the running. It is here that any visions I had of the Brownlees soon fade. Unlike many people who have taken up triathlons, I have no running background – combined with no natural skill. I only took up running a few years ago and have made little progress since then. So running 5km after a 750m swim and 20km cycle is going to prove a challenge.

Sideplank: good for lazy glutes. PR

Slogging along the canal tow paths during my lunch breaks wasn't getting me very far, so I jumped at the chance when I was invited to a training session with Olympic triathlete Stuart Hayes. Hayes, a former ITU Triathlon world cup winner, was part of the British Olympic team that helped the Brownlees secure their medals at the games. He tells me the run is his favourite event, so I get as many tips as I can, in the hope that his good form will rub off on me.

I actually woke up that morning at 4am in a cold sweat – I have to run with an Olympic triathlete!? – but fortunately, Hayes cycles alongside us as we run around the lake and I make the most of my opportunity to grill him – through gasps for air. Hayes says he spent 10 years getting injured, on and off, before learning to run properly, and that the key to all this is the glutes. It's common for runners to have glutes that have become inhibited or weak due to other muscles overworking. This is particularly common in triathletes, who spend a lot of time on the bike and so become quad dominant. Having a minor recurring knee injury from what I'm told is a lazy left quad, I'm keen to hear his advice. He takes us through a series of exercises designed to get the glutes firing before we start running. These include glute activation, the clam, one legged squats and a sort of side plank that causes my left glute to wake up with start. We then take another lap around the lake with glutes firing and it does feel different. I feel as if I am being pushed along from behind and I feel lighter on my feet – it's a revelation.

Hayes also emphasises the importance of nutrition and, after a chat with a Maxifuel nutritionist, it turns out I haven't been eating anywhere near enough carbohydrate for my training regime – which may explain why I am permanently hungry. For my weight and the amount of training I am doing I should be consuming roughly between 265g and 371g of carbohydrate, which equates to 20 slices of bread or 16 sweet potatoes! Fortunately, I'm told dried fruit or juice is also a good source of carbs, as are various supplements for when you just can't eat any more.

And so I head off armed with plenty of advice to pack into the last few training sessions. I'm full of carbohydrates and my glutes are fired up and ready. Blenheim Triathlon beckons this weekend – just time to get a few last tips in, so please share your advice on running in a triathlon below.